Brush head for toothbrush

ABSTRACT

A head for a toothbrush including a neck and, first and second sets of one or more bristles each. The first and second sets are indirectly supported by the neck and movable relative to each other such that at least one component of this relative movement causes the bristle(s) of the first set to be raised and/or lowered relative to the bristle(s) in the second set. The first and second sets of bristles both are movable relative to the neck.

[0001] This application is a continuation of U.S. patent applicationSer. No. 10/456,769 filed on Jun. 6, 2003 (still pending) which is acontinuation of U.S. patent application Ser. No. 09/425,423 filed Oct.22, 1999 (now U.S. Pat. No. 6,574,820).

FIELD OF THE INVENTION

[0002] The invention relates generally to the field of oral care, and inparticular to toothbrushes. More specifically, the invention relates toa brush head for a toothbrush.

BACKGROUND OF THE INVENTION

[0003] U.S. Pat. No. 5,577,285 (the '285 patent) discloses an electrictoothbrush with a rotary bristle supporting structure. In one embodimentof the invention shown in FIG. 6, the brush head is driven such that anouter ring of bristles 45 a and an inner ring of bristles 45 b are movedin an alternating rotary motion in opposite directions. While such anarrangement is beneficial for cleaning, for example, the bucal orlingual tooth surfaces, the lack of motion of any of the bristles in anup and down pattern results in a less than optimal cleaning of theinter-dental tooth surfaces.

[0004]FIG. 9 of the '285 patent discloses an additional embodiment ofthe invention in which all of the bristles 45 are rotated about an axis54 while also being moved in an up and down motion parallel to thisaxis. This embodiment will provide enhanced cleaning of the inter-dentaltooth surfaces. However, the fact that all of the bristles are moved upand down limits the depth of penetration that the bristles can obtainbetween the teeth. This is because while some of the bristles are tryingto penetrate between the teeth, others are pressing against, forexample, the bucal tooth surface, thus limiting the motion of the brushhead towards the teeth.

SUMMARY OF THE INVENTION

[0005] The present invention is directed to overcoming one or more ofthe problems set forth above. Briefly summarized, according to oneaspect of the present invention, a head for an electric toothbrush,includes a first bristle support which is rotatable about an axis and aplurality of first bristles extending from the first bristle support. Asecond bristle support includes a plurality of second bristles extendingfrom a surface of the second bristle support at an acute angle to thesurface.

[0006] These and other aspects, objects, features and advantages of thepresent invention will be more clearly understood and appreciated from areview of the following detailed description of the preferredembodiments and appended claims, and by reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a side view of an electric toothbrush head attached to abrush handle/drive;

[0008]FIG. 2 is an exploded side view of the toothbrush head;

[0009]FIG. 3A is a side view of the head with a central bristle in aretracted position;

[0010]FIG. 3B is a side view of the head with a central bristle in anextended position;

[0011]FIG. 4 is a top plan view of a second embodiment of an electrictoothbrush head;

[0012]FIG. 5 is a sectional view of FIG. 4 taken along the lines 5-5;

[0013]FIG. 6 is a sectional view of FIG. 5 taken along the lines 6-6;

[0014]FIG. 7 is a sectional view of FIG. 5 taken along the lines 7-7;

[0015]FIG. 8 is a sectional view similar to FIG. 5 of a third embodimentof the invention;

[0016]FIG. 9 is a sectional view of FIG. 8 taken along the lines 9-9;

[0017]FIG. 10 is a sectional view of FIG. 8 taken along the lines 10-10;

[0018]FIG. 11 is a sectional view of FIG. 8 taken along the lines 11-11;

[0019]FIG. 12 is a sectional view of FIG. 8 taken along the lines 12-12;

[0020]FIG. 13 is a perspective view of a fourth embodiment of atoothbrush head; and

[0021]FIG. 14 is a front view of the toothbrush head of FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

[0022] Beginning with FIG. 1, an electric toothbrush head 10 includes aneck 12 which is connected to a bristle support 14. Bristles 16 onsupport 14 are oscillated in a rotary movement through an arc of betweenabout +− 15 to 90 degrees, more preferably +− 20 to 50 degrees as in aconventional electric toothbrush.

[0023]FIG. 2 shows support 14 in an exploded side view. An interdentalprobe 18 is secured to a slider core 20 in the center of bristles 16.Probe 18 can be a single large bristle or a tuft of much smallerbristles. Alternatively, core 20 can be enlarged to accommodate aplurality of probes (not shown), one of which may be positioned in thecenter of the core (as in FIG. 1), with the remainder of the probesbeing positioned on the core away from its center.

[0024] A pair of cam follower pins 22 are secured to opposite sides ofthe lower portion of core 20. Core 20 is positioned inside of a brushbase 24 such that pins 22 are forced to ride along respective cam tracks26 as well as respective vertical slider tracks 28 (one slider track ishidden behind the other). A retaining pin 30 rides in a track 32 toretain base 24 within a housing 34. A guide/rotation pin 36 passesthrough a hole in the bottom of housing 34 and is secured to base 24.

[0025] Operation of support 14 will be explained with reference to FIGS.2, 3A and 3B. Pin 36 is oscillated about its long axis by a drivemechanism (not shown) in neck 12. The drive mechanism can be ofconventional design. Oscillation of pin 36 causes brush base 24 andbristles 16 to oscillate in a rotary pattern. Pin 30 retains base 24within housing 34. Oscillation of base 24 causes core 20 and probe 18 tooscillate with the base because pins 22 ride in track 28 of the base.Pins 22 also ride in respective tracks 26 in the housing, thus causingcore 20 and probe 18 to move up and down relative to bristles 16 duringoscillation of brush base 24. FIGS. 3A and 3B show that a preferredextension of probe 18 from its lowest to highest position is about 5 mm.

[0026] In an alternative embodiment, all of bristles 16 are eliminated,leaving only probe 18 for cleaning teeth. This embodiment would be usedprimarily for cleaning interdental spaces, not for cleaning the othersurfaces of teeth.

[0027] Turning to FIGS. 4-7, a second embodiment of the invention willbe described. A brushead 40 can be attached to a handpiece (not shown)of an electric toothbrush. A driveshaft (not shown) protrudes out of thehandpiece and can effect an oscillating rotation. Brushhead 40 includesa tube 42 in which a shaft 44 is located. The rear end of tube 42 fitsinto the housing (not shown) of the handpiece. Shaft 44 engages thedriveshaft of the handpiece. A pin 46 is press fitted into shaft 44. Pin46 can rotate at its free end in a bearing hole 48 in a front part 50 oftube 42. Axis 52 of pin 46 coincides with the axis of the driveshaft ofthe handpiece.

[0028] A pivot 54 can rotate in a bearing hole 56 situated in front part50 of tube 42. Pivot 54 is retained in hole 56 by a ring 58. A brushbase 60 is press fitted onto pivot 54. Brush base 60 has holes 62 inwhich tufts of bristles 64 are secured. A cross pin 66 is welded ontothe free end of pivot 54. Both ends of cross pin 66 retain brush base 60on pivot 54 by interaction with a shoulder 68 of the brush base. Thecentral part of cross pin 66 is placed in a bearing hole 70 of a rocker72. Rocker 72 can swivel about cross pin 66 and contains holes 74 inwhich tufts of bristles 76 are secured.

[0029] Shaft 44 includes a bearing hole 78 in which a drive rod 80 canmove. The distance between axis 52 of pin 46 and an axis 82 of drive rod80 is a radius r1. A stud 84 is welded onto the free end of drive rod80. The distance between an axis 86 of pivot 54 and an axis 88 of stud84 is a radius r2. Stud 84 can move in a bearing seat 90 in brush base60. At one end of stud 84 is carried a ball 92 which can move in acylindrical slot 94 in rocker 72.

[0030] When shaft 44 is oscillated about axis 52 through an angle of +−alpha 1 about pin 46, two different motions are induced. First, brushbase 60 and rocker 72 are oscillated in a rotating manner through anangle of +− beta 1 about pivot 54 in bearing hole 56. This oscillatingrotation causes bristles 64 to wipe plaque off teeth like a broom.Second, rocker 72 is oscillated in a rotating manner through an angle of+− gamma 1 about cross pin 66 in bearing hole 70. Oscillation of rocker72 about pin 66 causes bristle tufts 76 to loosen plaque like a chisel.Two cycles of oscillation of rocker 72 about pin 66 occur for every onecycle of oscillation of base 60 and rocker 72 about pivot 54. Therelations between the oscillation angles alpha 1 to beta 1 and alpha 1to gamma 1 depend only on radii r1 and r2.

[0031] Referring to FIGS. 8-12, a third embodiment of the invention willbe described. The third embodiment modifies the relationship between theoscillation angles, primarily to increase the gamma angle of theoscillating rotation of rocker 72. The basic features of the thirdembodiment remain unchanged from the second embodiment. The maindifference is in the location of the drive rod.

[0032] In the mid-position of the oscillating rotation of a shaft 100, adrive rod 102 is located at a distance e from a median plane 104 of abrushhead 106. A stud 108 is welded laterally on a free end of drive rod102 with a distance e between the centerlines. Stud 108 is movable in abearing seal 110 of a brush base 112. When a drive shaft 114 is in amid-oscillation position, stud 108 is in a median plane 116 of brushbase 112. Drive rod 102 can move in a bearing hole 118 in shaft 114.Bearing hole 118 is situated in the distance e from median plane 104 ofshaft 114 when the shaft is in its mid-oscillation position.

[0033] When shaft 114 is oscillated about median plane 104 through anangle of +− alpha 1, two different motions are induced. First, brushbase 112 and rocker 72 are oscillated in a rotating manner through anangle of +− beta 2 which is smaller than +beta 1 about axis 120. Second,rocker 72 is oscillated in a rotating manner through an angle of +−gamma 2 which is bigger than +− gamma 1 about cross pin 66. Therelations between the oscillation angles alpha 1 to beta 2 and alpha 1to gamma 2 depend on radii r1 and r2 as well as on the distance e.

[0034] In embodiments 2 and 3 of the invention, one component of therocking motion of rocker 72 causes bristles 76 to move up and down (i.e.substantially parallel to pivot 54) relative to bristles 64.

[0035]FIGS. 13 and 14 disclose a toothbrush head 130 which is similar infunction to the head of FIG. 4. The major difference is that tufts ofbristles 132 are tilted away from the perpendicular (to the top surfaceof a pivot bar 138) at an angle 134 of between about 1-20 degrees.Preferably the bristles are tilted along the direction of oscillation ofbristles 136. Such tilting of bristles 132 provides better interdentalpenetration during the respective upstrokes of pivot bar 138,particularly for the tuft(s) on bar 138 which are being moved by head138 in the tilt direction. It is preferable that tufts of bristles onboth sides of bar 138 have the same tilt angle and are tilted in thesame direction (i.e. in the same plane). Alternatively, tufts ofbristles on opposite sides of the bar can be tilted in oppositedirections.

[0036] The invention has been described with reference to severalembodiments including a preferred embodiment. However, it will beappreciated that variations and modifications can be effected by aperson of ordinary skill in the art without departing from the scope ofthe invention.

1. A head for an electric toothbrush, comprising: a first bristlesupport which is rotatable about an axis; a plurality of first bristlesextending from the first bristle support; a second bristle support; anda plurality of second bristles extending from a surface of the secondbristle support at an acute angle to the surface.
 2. The head of claim1, wherein the first bristle support is rotatable in an oscillatingmanner about the axis.
 3. The head of claim 1, wherein the firstbristles extend substantially perpendicular from the first bristlesupport.
 4. The head of claim 1, wherein the second bristles are angledtowards at least some of the first bristles.
 5. The head of claim 1,wherein the second bristles are angled away from at least some of thefirst bristles.